base: Stop passing a non-const ref to ObserverListBase::Iterator.

ui/compositor/layer_animator.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/compositor/layer_animator.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/animation/animation_id_provider.h"
@@ skipping 783 matching lines @@
 void LayerAnimator::GetTargetValue(
     LayerAnimationElement::TargetValue* target) const {
   for (AnimationQueue::const_iterator iter = animation_queue_.begin();
        iter != animation_queue_.end(); ++iter) {
     (*iter)->GetTargetValue(target);
   }
 }
 
 void LayerAnimator::OnScheduled(LayerAnimationSequence* sequence) {
   if (observers_.might_have_observers()) {
-    ObserverListBase<LayerAnimationObserver>::Iterator it(observers_);
+    ObserverListBase<LayerAnimationObserver>::Iterator it(&observers_);
     LayerAnimationObserver* obs;
     while ((obs = it.GetNext()) != NULL) {
       sequence->AddObserver(obs);
     }
   }
   sequence->OnScheduled();
 }
 
 void LayerAnimator::SetTransitionDuration(base::TimeDelta duration) {
   if (is_transition_duration_locked_)
@@ skipping 37 matching lines @@
 }
 
 LayerAnimator::RunningAnimation::RunningAnimation(
     const base::WeakPtr<LayerAnimationSequence>& sequence)
     : sequence_(sequence) {
 }
 
 LayerAnimator::RunningAnimation::~RunningAnimation() { }
 
 }  // namespace ui